The aim of this research is to develop and perform proof of concept in vitro testing of an ultrasonic technique for imaging periodontal structures. This technique will allow accurate measurements of disease activity for patient risk assessment and treatment outcome evaluation without the need for ionizing radiography and manual periodontal probing. The objective is to gather data from a variety of clinical studies using a prototype intra-oral ultrasound instrument. The first planned study is a comparison of the ultrasonic instrument to manual probing and controlled force probing of human patients. In the second study, human patients will be scanned prior to gum flap surgery and then the ultrasonic signals will be correlated to periodontal structures identified during the surgical procedure. In the third planned study, human patients will be scanned prior to an en bloc procedure, where a block of the jaw is removed due to disease. The ultrasound scans will be compared against the gold-standard of histology subsequently performed on the annotated en bloc samples. Additional planned studies include comparison to histology performed on extracted teeth and recently decreased cadaver jaws. All of the data will be used to refine the technique, improve the analysis of scan signals, and develop the framework of the software that will be used during the subsequent in vitro testing program. PROPOSED COMMERCIAL APPLICATION: It is intended to produce a sufficient volume of data to show reduced viability and improved ease of use, in comparison to conventional manual periodontal probing, and to establish the ultrasound periodontal probe as a clinically-valuable tool for patient assessment and the first non-invasive measure of periodontal disease activity.